/*
 * Lazy Load - jQuery plugin for lazy loading images
 *
 * Copyright (c) 2007-2013 Mika Tuupola
 *
 * Licensed under the MIT license:
 *   The MIT License | Open Source Initiative
 *
 * Project home:
 *   Lazy Load Remastered
 *
 * Version:  1.9.3
 *
 */

(function($, window, document, undefined) {
	var $window = $(window);

	$.fn.lazyload = function(options) {
			var elements = this;
			var $container;
			var settings = {
					threshold       : 0,
					failure_limit   : 0,
					event           : "scroll",
					effect          : "show",
					container       : window,
					data_attribute  : "original",
					skip_invisible  : true,
					appear          : null,
					load            : null,
					placeholder     : ""
			};

			function update() {
					var counter = 0;

					elements.each(function() {
							var $this = $(this);
							if (settings.skip_invisible && !$this.is(":visible")) {
									return;
							}
							if ($.abovethetop(this, settings) ||
									$.leftofbegin(this, settings)) {
											/* Nothing. */
							} else if (!$.belowthefold(this, settings) &&
									!$.rightoffold(this, settings)) {
											$this.trigger("appear");
											/* if we found an image we'll load, reset the counter */
											counter = 0;
							} else {
									if (++counter > settings.failure_limit) {
											return false;
									}
							}
					});

			}

			if(options) {
					/* Maintain BC for a couple of versions. */
					if (undefined !== options.failurelimit) {
							options.failure_limit = options.failurelimit;
							delete options.failurelimit;
					}
					if (undefined !== options.effectspeed) {
							options.effect_speed = options.effectspeed;
							delete options.effectspeed;
					}

					$.extend(settings, options);
			}

			/* Cache container as jQuery as object. */
			$container = (settings.container === undefined ||
										settings.container === window) ? $window : $(settings.container);

			/* Fire one scroll event per scroll. Not one scroll event per image. */
			if (0 === settings.event.indexOf("scroll")) {
					$container.bind(settings.event, function() {
							return update();
					});
			}

			this.each(function() {
					var self = this;
					var $self = $(self);

					self.loaded = false;

					/* If no src attribute given use data:uri. */
					// if ($self.attr("src") === undefined || $self.attr("src") === false) {
					// 		if ($Self("img")) {
					// 				$self.attr("src", settings.placeholder);
					// 		}
					// }

					/* When appear is triggered load original image. */
					$self.one("appear", function() {
							if (!this.loaded) {
									if (settings.appear) {
											var elements_left = elements.length;
											settings.appear.call(self, elements_left, settings);
									}
									$("<img />")
											.bind("load", function() {

													var original = $self.attr("data-" + settings.data_attribute);
													$self.hide();
													if ($self.is("img")) {
															$self.attr("src", original);
													} else {
															$self.css("background-image", "url('" + original + "')");
													}
													$self[settings.effect](settings.effect_speed);

													self.loaded = true;

													/* Remove image from array so it is not looped next time. */
													var temp = $.grep(elements, function(element) {
															return !element.loaded;
													});
													elements = $(temp);

													if (settings.load) {
															var elements_left = elements.length;
															settings.load.call(self, elements_left, settings);
													}
											})
											.attr("src", $self.attr("data-" + settings.data_attribute));
							}
					});

					/* When wanted event is triggered load original image */
					/* by triggering appear.                              */
					if (0 !== settings.event.indexOf("scroll")) {
							$self.bind(settings.event, function() {
									if (!self.loaded) {
											$self.trigger("appear");
									}
							});
					}
			});

			/* Check if something appears when window is resized. */
			$window.bind("resize", function() {
					update();
			});

			/* With IOS5 force loading images when navigating with back button. */
			/* Non optimal workaround. */
			if ((/(?:iphone|ipod|ipad).*os 5/gi).test(navigator.appVersion)) {
					$window.bind("pageshow", function(event) {
							if (event.originalEvent && event.originalEvent.persisted) {
									elements.each(function() {
											$(this).trigger("appear");
									});
							}
					});
			}

			/* Force initial check if images should appear. */
			$(document).ready(function() {
					update();
			});

			return this;
	};

	/* Convenience methods in jQuery namespace.           */
	/* Use as  $.belowthefold(element, {threshold : 100, container : window}) */

	$.belowthefold = function(element, settings) {
			var fold;

			if (settings.container === undefined || settings.container === window) {
					fold = (window.innerHeight ? window.innerHeight : $window.height()) + $window.scrollTop();
			} else {
					fold = $(settings.container).offset().top + $(settings.container).height();
			}

			return fold <= $(element).offset().top - settings.threshold;
	};

	$.rightoffold = function(element, settings) {
			var fold;

			if (settings.container === undefined || settings.container === window) {
					fold = $window.width() + $window.scrollLeft();
			} else {
					fold = $(settings.container).offset().left + $(settings.container).width();
			}

			return fold <= $(element).offset().left - settings.threshold;
	};

	$.abovethetop = function(element, settings) {
			var fold;

			if (settings.container === undefined || settings.container === window) {
					fold = $window.scrollTop();
			} else {
					fold = $(settings.container).offset().top;
			}

			return fold >= $(element).offset().top + settings.threshold  + $(element).height();
	};

	$.leftofbegin = function(element, settings) {
			var fold;

			if (settings.container === undefined || settings.container === window) {
					fold = $window.scrollLeft();
			} else {
					fold = $(settings.container).offset().left;
			}

			return fold >= $(element).offset().left + settings.threshold + $(element).width();
	};

	$.inviewport = function(element, settings) {
			 return !$.rightoffold(element, settings) && !$.leftofbegin(element, settings) &&
							!$.belowthefold(element, settings) && !$.abovethetop(element, settings);
	 };

	/* Custom selectors for your convenience.   */
	/* Use as $("img:below-the-fold").something() or */
	/* $("img").filter(":below-the-fold").something() which is faster */

	$.extend($.expr[":"], {
			"below-the-fold" : function(a) { return $.belowthefold(a, {threshold : 0}); },
			"above-the-top"  : function(a) { return !$.belowthefold(a, {threshold : 0}); },
			"right-of-screen": function(a) { return $.rightoffold(a, {threshold : 0}); },
			"left-of-screen" : function(a) { return !$.rightoffold(a, {threshold : 0}); },
			"in-viewport"    : function(a) { return $.inviewport(a, {threshold : 0}); },
			/* Maintain BC for couple of versions. */
			"above-the-fold" : function(a) { return !$.belowthefold(a, {threshold : 0}); },
			"right-of-fold"  : function(a) { return $.rightoffold(a, {threshold : 0}); },
			"left-of-fold"   : function(a) { return !$.rightoffold(a, {threshold : 0}); }
	});

})(jQuery, window, document);